Research and development in microelectronics have continued to produce astounding progress in MEMS technology, though MEMS technology continues to rely upon conventional processing. In layman's terms, MEMS are the “eyes” and “arms” that provide the ability to sense and control the environment of a device. MEMS technologies are becoming ever more prevalent in society every day. Use of MEMS technology has limitless applications through modular measurement devices such as accelerometers, gyroscopes, actuators, microphones, and sensors including pressure sensors and inertial sensors.
MEMS devices such as micro-machined accelerometers are highly desirable for inertial navigation and stability control. Various micro-machined accelerometers have been developed based on capacitive, piezoresistive, resonant, tunneling, thermal, or piezoelectric sensing methods.
MEMS based inertial measurement units (IMU) are ubiquitous and are used in domains such as heavy industry, transportation, utilities and energy, and consumer electronics. Market projections anticipate large growth for MEMS based IMU in consumer electronics, such as in cell phones and tablets. Further, there is expected growth for wearable gadgets. To meet projections, the growing trend of IMU technology is reduction in size and reduction in cost. Specifically, wearable gadgets and other consumer goods place a premium on product size and thus, on the MEMS device footprint within the product.
Accordingly, it is desirable to provide an improved three-axis MEMS accelerometer and method for fabricating such a MEMS accelerometer. Further, it is desirable to provide a monolithic MEMS device including both a capacitive accelerometer and a piezo accelerometer. Also, it is desirable to provide a method for fabricating integrated capacitive and piezo accelerometers, such as on a monolithic substrate. Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background.